Di2 Battery Holder for 25.4 mm Seat Posts


This battery holder is for Shimano Di2 internal SM-BTR2 and BT-DN110 batteries. The battery fits inside the seat post and typically requires a seat post made specifically for Di2. This holder allows the battery to be held securely within a non-Di2 specific 25.4mm seat post found on many bikes from 2014 to present. It will also fit other seat posts with the same inside diameter.
Weight: 6-7g

Made from a flexible plastic material.  Fits very tightly.

Battery Holder Sizes

We make Di2 battery holders for 25.4mm seat posts with various inside diameter size options.  If you are using a seatpost not listed here, please contact us for assistance.

Cannondale® Branded

C2 - 19 mm ID (Carbon)

C3 - 19.5 mm ID (Aluminum)

SAVE - (unmodified)

Focus® Branded

BBB Basic - 19.65 mm ID (Aluminum)

FSA® Branded

SLK Carbon - 20.5 mm ID (Carbon)

Zipp® Branded

Zipp Service Course SL Carbon - 22 mm mm ID (Carbon)


Why use a holder instead of tape or foam?

Ad hoc solutions using tape and foam have multiple issues. The net result is often a damaged or stuck battery.

Problems with Tape or Foam:

  • They don't protect the delicate battery connection
  • Tape or foam can shrink, causing the battery to fall out
  • They can cause the battery to overheat
  • Tape, especially, can fuse to the inside of the seat post




How to Remove the Poly Holder

Removing the holder requires pliers.  Never use pliers on the battery itself.

  1. Grip the flat surface of the holder with pliers.
  2. While holding the pliers steady, rotate the seat post while gently pulling it away from the pliers.
  3. When the holder is about 1/2" (10-15mm) extracted, release the pliers.
  4. The holder and battery can now be removed by hand.



Returning Customers Please Read

Free Replacement Quarter-Turn Insert

If you had previously purchased a Garmin mount between May 2021 and February 2022 you may be eligible for a free quarter-turn insert replacement. Please read this article to see if your mount is affected.